As a construction machine including an engine and equipment for cooling of the engine, there has been known a construction machine disclosed in Japanese Unexamined Patent Publication No. 2001-193102 and Japanese Unexamined Patent Publication No. 2005-16321. The construction machine disclosed therein includes a cooling fan that takes the air for cooling into an engine room and an exhaust duct for discharging the air in the engine room to the outside of the engine room. The exhaust duct extends along an axial flow direction of the cooling fan on the inner side of an engine hood located on the upper side of the engine room. The air is discharged in the axial flow direction through the exhaust duct. A passage formed by such an exhaust duct can be a route which allows noise caused by an engine and the like in the engine room to leak to the outside. Therefore, it is desired to attenuate the noise in the exhaust duct by sufficiently securing a duct length of the exhaust duct.
The structure shown in FIG. 2 of Japanese Unexamined Patent Publication No. 2005-16321 includes a post-treatment device for treating exhaust gas from the engine, the device projecting upward from the engine room and located on an extended line of the exhaust duct. The post-treatment device or a projection element similar to the post-treatment device can be an obstacle limiting the duct length of the exhaust duct when the size thereof is increased. The limitation of the duct length obstructs suppression of the leak of the noise through the exhaust duct. Furthermore, the projection element may interfere with the air discharged from the exhaust duct to thereby prevent the air from smooth discharge.